THE NERVOUS SYSTEM

1. THE NERVOUS SYSTEM

2. The Functions of the Nervous System The nervous system coordinates and controls body activity The nervous system detects and processes internal and external information and formulates appropriate responses

3. The Structures of the Nervous System • There are two major divisions of the nervous system: • The central nervous system (CNS) consists of the brain and spinal cord • The peripheral nervous system (PNS) consists of the cranial and spinal nerves, autonomic nervous system.

4. The Structures of the Nervous System • The basic unit of the nervous system is the neuron • There are three types of neurons: • sensory (also called afferent) • associative • motor (also called efferent)

5. Parts of the Neuron • The neuron consists of • a cell body (soma) • dendrites • Carry impulses toward the cell body • an axon • Carries impulses away from the cell body

6. The Gap • The space between two neurons or between a neuron and receptor is the synapse • Chemical substances called neuro-transmitters are released into the space to allow information to be relayed

7. Surrounding Structures • Myelin is a protective covering over some nerve cells including parts of the spinal cord • Myelin serves as an electrical insulator • Myelin is interrupted at regular intervals along the length of a fiber by gaps called nodes of Ranvier

8. Activity time!

9. The CNS The central nervous system is made up of the brain and spinal cord

10. The Meninges • The meninges are a three-layered membrane that surrounds the CNS • The three layers of the meninges are the dura mater, arachnoid membrane, and the pia mater

11. The CSF • Cerebrospinal fluid (CSF) is the clear, colorless ultrafiltrate that nourishes, cools, and cushions the CNS • CSF is made by the choroid plexus that lines the ventricles of the brain

12. The Brain • The brain is the enlarged and highly developed portion of the CNS that lies in the skull and is the main site of nervous control • The cranium is the portion of the skull that encases the brain

13. Lobes all around! • Frontal Lobe- planning, reasoning, judgment, and memory • Temporal Lobe – speech, auditory perception, and emotions • Parietal Lobe – touch, numbers, taste, and temperature. • Occipital Lobe – color recognition, visual perception

14. The Brain Divisions • The brain is divided into three main parts: • Cerebrum is the largest part and is responsible for receiving and processing information • Cerebellum is the second largest part that coordinates muscle activity • Brainstem connects the cerebral hemispheres with the spinal cord and supports basic life functions

15. The Spinal Cord • The spinal cord is the continuation of the medulla oblongata of the brainstem • The spinal cord passes through an opening in the occipital bone called the foramen magnum • The spinal cord carries the tracts that influence the innervation of the limbs and lower part of the body and is the pathway for impulses going to and from the brain

16. The Discs • The spinal cord is housed within vertebrae to protect it from injury • The vertebrae are protected from each other by intervertebral discs located between the vertebrae • Intervertebral discs are layers of fibrocartilage that form pads separating and cushioning the vertebrae from each other

17. The PNS • The peripheral nervous system consists of cranial & spinal nerves and the autonomic nervous system • The spinal nerves arise from the spinal cord and supply sensory and motor fibers to the body region associated with their emergence from the spinal cord.

18. The ANS • The autonomic nervous system is that part of the peripheral nervous system that innervates smooth muscle, cardiac muscle, and glands • There are two divisions of the ANS: • sympathetic: fight or flight • parasympathetic: maintains normal body function

19. Review

20. Nervous System http://www.youtube.com/watch?v=UabDiuTtU0M